Leiden University Student Repository

Oikonomeas Koppasis, Nikolaos (2020)

Using In-line Digital Holography for Measuring the Diffusion of Active Janus Spheres

Master thesis | Physics (MSc)

We use Inline Digital Holography to measure the diffusion coefficient of spherical colloids with a 1.06mm radius in the bulk of a liquid. We obtain a diffusion coefficient of 0.23 +/- 0.03mm2/s which is in good agreement with Stokes-Einstein theory. We attempt the measurements to active Janus colloid spheres and explore the possibilities and limitations of the technique. We use the Discrete Dipole Approximation to fit the holograms to the Lorenz-Mie theory and report on the viability of the computation. We discuss the minimum necessary requirements for performing a successful fitting and analysis of the motion of Janus colloid spheres, in the bulk of a medium, using inline holography

Diffusion

Jannus Sphere

Holography

Colloids

Soft Matter

Author

Oikonomeas Koppasis, Nikolaos

Faculty

Faculty of Science

Specialisation

Research in Physicsm, Soft and Biological Matter

Supervisors

Kraft, Daniela

ECTS Credits

3

Language

en